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Endometrial amoebiasis

Othman NH, Ismail AN

Eur J Obstet Gynecol Reprod Biol, 1993 Dec 15;52(2):135-7.
PMID: 8157142

A case of endometrial infection by Entamoeba histolytica is described in an elderly lady who presented with profuse vaginal discharge and was clinically misdiagnosed as endometrial carcinoma.

Matched MeSH terms: Entamoebiasis/diagnosis*
Fulltext Molecular detection of Entamoeba histolytica and Entamoeba dispar infection among wild rats in Kuala Lumpur, Malaysia

Lau YL, Jamaiah I, Rohela M, Fong MY, Siti CO, Siti FA

Trop Biomed, 2014 Dec;31(4):721-7.
PMID: 25776597 MyJurnal

Entamoeba histolytica infection is the third-greatest parasitic disease responsible for death in the world. Wild rats harbouring E. histolytica can be the possible reservoir hosts for human amoebiasis. There were numerous studies on prevalence of intestinal parasites among wild rats in Malaysia but none has reported E. histolytica. Rats were captured from Sentul and Chow Kit areas, Kuala Lumpur, Malaysia. The preserved stool samples were used for microscopy examination and molecular analysis. Out of 137 samples collected, 12 were positive for E. histolytica / E. dispar / E. moshkovskii microscopically. Two E. histolytica (1.4%), 1 E. dispar (0.7%) and 6 mixed infections of E. histolytica and E. dispar (4.3%) were detected using PCR. This is the first report of molecular detection of E. histolytica/dispar infection among wild rats in Malaysia. This study provides useful information about the potential risks of zoonotic agents and the importance of developing control measures to prevent zoonotic transmission.

Matched MeSH terms: Entamoebiasis/diagnosis
Fulltext Public health and clinical importance of amoebiasis in Malaysia: a review

Tengku SA, Norhayati M

Trop Biomed, 2011 Aug;28(2):194-222.
PMID: 22041740 MyJurnal

Entamoeba histolytica, the causative agent of human amoebiasis remains a significant cause of morbidity and mortality in developing countries and is responsible for up to 100,000 deaths worldwide each year. Entamoeba dispar, morphologically indistinguishable from E. histolytica is more common in humans in many parts of the world. Similarly Entamoeba moshkovskii, which was long considered to be a free-living amoeba is also morphologically identical to E. histolytica and E. dispar, and is highly prevalent in some E. histolytica endemic countries. Humans are the host of infection and there would not appear to be other meaningful animal reservoirs of E. histolytica. Entamoeba. histolytica can be present in sewage and contaminated water. The infection is mainly transmitted via ingestion of water or food contaminated by faeces containing E. histolytica cysts. Clinical features of amoebiasis range from asymptomatic colonization to amoebic dysentery and invasive extraintestinal amoebiasis, which is manifested most commonly in the form of abscesses in liver and lungs. The epidemiology of amoebiasis has dramatically changed since the separation of E. histolytica and E. dispar species and the worldwide prevalence of these species has not been estimated until recently. Morever, E. moshkovskii, another morphologically indistinguishable human parasitic Entamoeba was not mentioned or considered as a contributor to the prevalence figures in endemic areas. Amoebiasis is still a major health problem especially in aboriginal settlements and amongst people living in remote area in Malaysia. However, until now there is only one data currently available to indicate the true prevalence and incidence of E. histolytica and E. dispar. Further studies are needed to determine the burden of E. histolytica, E. dispar and E. moshkovskii infections in Malaysia. In the present review, we briefly summarize all methods use in diagnosing Entamoeba species, ranging from microscopic identification to molecular detection such as culture and isoenzyme analysis, antibody detection tests, antigen detection tests, immunochromatographic assays, conventional PCR, real-time PCR and loop-mediated isothermal amplification (LAMP).

Matched MeSH terms: Entamoebiasis/diagnosis
Fulltext Use of molecular tools to distinguish Entamoeba histolytica and Entamoeba dispar infection among the aborigines in Cameron Highlands

Noor Azian MY, Lokman Hakim S, Maslawaty MN

Trop Biomed, 2006 Jun;23(1):31-6.
PMID: 17041549 MyJurnal

Amoebiasis is an infectious diseased caused by parasitic one-celled protozoan called Entamoeba histolytica. Numerous protozoa also can inhabit the gastro-intestinal tract of human. Majority of these protozoa are non-pathogenic commensals or only causes disease under certain circumstances. Morphologically, E. histolytica, the invasive form, share the same characteristic with the nonpathogenic form, E. dispar. Both strains can be distinguished by using DNA identification. Many previous researches in Malaysia only reported infection with E. histolytica infection. Therefore in this study we tried to classify infection among the aborigines in Cameron Highland as true E. histolytica or E. dispar by Nested Polymerase Chain Reaction (Nested PCR) and Restriction enzyme (RE) digestion. Results showed that 31 samples were positive by microscopic examination, however of these 28 (13.2%) samples were positive for E. histolytica and 12 (5.6%) samples were positive for E. dispar by molecular tools.

Matched MeSH terms: Entamoebiasis/diagnosis*
Development of a thermostabilised triplex LAMP assay with dry-reagent four target lateral flow dipstick for detection of Entamoeba histolytica and non-pathogenic Entamoeba spp

Foo PC, Chan YY, Mohamed M, Wong WK, Nurul Najian AB, Lim BH

Anal Chim Acta, 2017 May 08;966:71-80.
PMID: 28372729 DOI: 10.1016/j.aca.2017.02.019

This study highlighted the development of a four target nitrocellulose-based nucleic acid lateral flow immunoassay biosensor in a dry-reagent strip format for interpretation of double-labelled double-stranded amplicons from thermostabilised triplex loop-mediated isothermal amplification assay. The DNA biosensor contained two test lines which captured biotin and texas red labelled amplicons; a LAMP internal amplification control line that captured digoxigenin labelled amplicon; and a chromatography control line that validated the functionality of the conjugated gold nanoparticles and membrane. The red lines on detection pad were generated when the gold nanoparticles conjugated antibody bound to the fluorescein labelled amplicons, and the capture agents bound to their specific hapten on the other 5' end of the double-stranded amplicon. The applicability of this DNA biosensor was demonstrated using amoebiasis-causing Entamoeba histolytica simultaneously with the non-pathogenic but morphologically identical Entamoeba dispar and Entamoeba moshkovskii. The biosensor detection limit was 10 E. histolytica trophozoites, and revealed 100% specificity when it was evaluated against 3 medically important Entamoeba species and 75 other pathogenic microorganisms. Heat stability test showed that the biosensor was stable for at least 181 days at ambient temperature. This ready-to-use and cold-chain-free biosensor facilitated the post-LAMP analysis based on visualisation of lines on strip instead of observation of amplicon patterns in agarose gel.

Matched MeSH terms: Entamoebiasis/diagnosis
Fulltext Real-time PCR assay in differentiating Entamoeba histolytica, Entamoeba dispar, and Entamoeba moshkovskii infections in Orang Asli settlements in Malaysia

Lau YL, Anthony C, Fakhrurrazi SA, Ibrahim J, Ithoi I, Mahmud R

Parasit Vectors, 2013;6(1):250.
PMID: 23985047 DOI: 10.1186/1756-3305-6-250

Amebiasis caused by Entamoeba histolytica is the third leading cause of death worldwide. This pathogenic amoeba is morphologically indistinguishable from E. dispar and E. moshkovskii, the non-pathogenic species. Polymerase chain reaction is the current method of choice approved by World Health Organization. Real-time PCR is another attractive molecular method for diagnosis of infectious diseases as post-PCR analyses are eliminated and turnaround times are shorter. The present work aimed to compare the results of Entamoeba species identification using the real-time assay against the established nested PCR method.

Matched MeSH terms: Entamoebiasis/diagnosis*
Fulltext Prevalence and risk factors associated with Entamoeba histolytica/dispar/moshkovskii infection among three Orang Asli ethnic groups in Malaysia

Shahrul Anuar T, M Al-Mekhlafi H, Abdul Ghani MK, Osman E, Mohd Yasin A, Nordin A, et al.

PLoS One, 2012;7(10):e48165.
PMID: 23133561 DOI: 10.1371/journal.pone.0048165

BACKGROUND: Entamoeba histolytica/Entamoeba dispar/Entamoeba moshkovskii infection is still prevalent in rural Malaysia especially among Orang Asli communities. Currently, information on prevalence of this infection among different ethnic groups of Orang Asli is unavailable in Malaysia. To contribute to a better comprehension of the epidemiology of this infection, a cross-sectional study aimed at providing the first documented data on the prevalence and risk factors associated with E. histolytica/E. dispar/E. moshkovskii infection was carried out among three Orang Asli ethnic groups (Proto-Malay, Negrito, and Senoi) in selected villages in Negeri Sembilan, Perak, and Pahang states, Malaysia.
METHODS/FINDINGS: Faecal samples were examined by formalin-ether sedimentation and trichrome staining techniques. Of 500 individuals, 8.7% (13/150) of Proto-Malay, 29.5% (41/139) of Negrito, and 18.5% (39/211) of Senoi were positive for E. histolytica/E. dispar/E. moshkovskii, respectively. The prevalence of this infection showed an age-dependency relationship, with higher rates observed among those aged less than 15 years in all ethnic groups studied. Multivariate analysis confirmed that not washing hands after playing with soils or gardening and presence of other family members infected with E. histolytica/E. dispar/E. moshkovskii were significant risk factors of infection among all ethnic groups. However, eating with hands, the consumption of raw vegetables, and close contact with domestic animals were identified as significant risk factors in Senoi.
CONCLUSIONS: Essentially, the findings highlighted that E. histolytica/E. dispar/E. moshkovskii parasites are still prevalent in Malaysia. Further studies using molecular approaches to distinguish the morphologically identical species of pathogenic, E. histolytica from the non-pathogenic, E. dispar and E. moshkovskii are needed. The establishment of such data will be beneficial for the public health authorities in the planning and implementation of specific prevention and control strategies of this infection in different Orang Asli ethnic groups in Malaysia.

Matched MeSH terms: Entamoebiasis/diagnosis
Evaluation of formalin-ether sedimentation and trichrome staining techniques: its effectiveness in detecting Entamoeba histolytica/dispar/moshkovskii in stool samples

Anuar TS, Al-Mekhlafi HM, Abdul Ghani MK, Abu Bakar E, Azreen SN, Salleh FM, et al.

J Microbiol Methods, 2013 Mar;92(3):344-8.
PMID: 23361047 DOI: 10.1016/j.mimet.2013.01.010

This study was conducted to evaluate two routinely microscopic diagnostic methods in comparison with single-round PCR assay as the reference technique to detect Entamoeba histolytica/dispar/moshkovskii. Examination was performed on 500 stool samples obtained from Orang Asli communities in different states of Malaysia using formalin-ether sedimentation, trichrome staining and single-round PCR techniques. Ninety-three stool samples were detected E. histolytica/dispar/moshkovskii positive by routine microscopy, while single-round PCR detected 106 positive samples. Additional positives detected by PCR assay were eventually confirmed to be negative by both microscopic techniques. Detection rate of E. histolytica/dispar/moshkovskii was highest in combination techniques (18.6%), followed by trichrome staining (13.4%) and formalin-ether sedimentation (11.2%) techniques. Single-round PCR detected 21.2% of the stool samples. The sensitivity and specificity of formalin-ether sedimentation and trichrome staining techniques compared to the reference technique were 31.1% (95% CI: 29.0-36.0) and 94.2% (95% CI: 89.8-98.9), and 53.8% (95% CI: 46.0-76.2) and 97.5% (95% CI: 92.8-99.1), respectively. However, the sensitivity [59.4% (95% CI: 48.9-78.5)] of the method increased when both techniques were performed together, but the specificity decreased to 92.4% (95% CI: 81.0-98.0). The agreement between the reference technique, trichrome staining and combination techniques were statistically significant by Kappa statistics (trichrome staining: K = 0.592, p < 0.05; combination techniques: K = 0.543, p < 0.05). Hence, the combination technique is recommended to be used as a screening method in the diagnosis of E. histolytica/dispar/moshkovskii infections either for clinical or epidemiological study.

Matched MeSH terms: Entamoebiasis/diagnosis*
Development of a thermostabilized, one-step, nested, tetraplex PCR assay for simultaneous identification and differentiation of Entamoeba species, Entamoeba histolytica and Entamoeba dispar from stool samples

Foo PC, Chan YY, See Too WC, Tan ZN, Wong WK, Lalitha P, et al.

J Med Microbiol, 2012 Sep;61(Pt 9):1219-1225.
PMID: 22556327 DOI: 10.1099/jmm.0.044552-0

Entamoeba histolytica is the only Entamoeba species that causes amoebiasis in humans. Approximately 50 million people are infected, with 100, 000 deaths annually in endemic countries. Molecular diagnosis of Entamoeba histolytica is important to differentiate it from the morphologically identical Entamoeba dispar to avoid unnecessary medication. Conventional molecular diagnostic tests require trained personnel, cold-chain transportation and/or are storage-dependent, which make them user-unfriendly. The aim of this study was to develop a thermostabilized, one-step, nested, tetraplex PCR assay for the detection of Entamoeba histolytica, Entamoeba dispar and Entamoeba species in cold-chain-free and ready-to-use form. The PCR test was designed based on the Entamoeba small subunit rRNA (SSU-rRNA) gene, which detects the presence of any Entamoeba species, and simultaneously can be used to differentiate Entamoeba histolytica from Entamoeba dispar. In addition, a pair of primers was designed to serve as an internal amplification control to help identify inhibitors in the samples. All PCR reagents together with the designed primers were thermostabilized by lyophilization and were stable at 24 °C for at least 6 months. The limit of detection of the tetraplex PCR was found to be 39 pg DNA or 1000 cells for Entamoeba histolytica and 78 pg DNA or 1000 cells for Entamoeba dispar, and the specificity was 100 %. In conclusion, this cold-chain-free, thermostabilized, one-step, nested, multiplex PCR assay was found to be efficacious in differentiating Entamoeba histolytica from other non-pathogenic Entamoeba species.

Matched MeSH terms: Entamoebiasis/diagnosis*
Fulltext Production of recombinant Entamoeba histolytica pyruvate phosphate dikinase and its application in a lateral flow dipstick test for amoebic liver abscess

Saidin S, Yunus MH, Zakaria ND, Razak KA, Huat LB, Othman N, et al.

BMC Infect Dis, 2014 Apr 04;14:182.
PMID: 24708664 DOI: 10.1186/1471-2334-14-182

BACKGROUND: Amoebic liver abscess (ALA) is the most common clinical manifestation of extraintestinal amoebiasis especially in developing countries, causing up to 100 000 fatal cases annually. Accurate and early diagnosis is important to prevent the disease complications, however its diagnosis still poses many challenges due to the limitations of the available detection tools. Pyruvate phosphate dikinase (PPDK), an excretory-secretory protein of E. histolytica, has been reported as a potential diagnostic marker for ALA, hence it may be exploited in the development of a new test for ALA.
METHODS: Recombinant PPDK (rPPDK) was expressed, purified and evaluated by Western blot. In parallel, recombinant galactose-and-N-acetyl-D-galactosamine inhibitable lectin (Gal/GalNAc lectin) was produced and tested similarly. The protein identity was confirmed by analysis using MALDI-TOF/TOF. A lateral flow dipstick (LFD) test using rPPDK was subsequently developed (rPPDK-LFD) and evaluated for serodiagnosis of ALA.
RESULTS: rPPDK was expressed as soluble protein after 4 hours of induction with 1 mM isopropyl β-D-1-thiogalactopyranoside (IPTG) at 30°C. Purification using nickel-nitrilotriacetic acid (Ni-NTA) resin yielded 1.5 mg of rPPDK from 1 L of culture with estimated molecular mass of 98 kDa on SDS-PAGE. Western blots using sera from patients with ALA, healthy individuals and other diseases probed with anti-human IgG4-HRP showed the highest sensitivity (93.3%) and specificity (100%); as compared to blots using IgG and IgG1 as secondary antibodies. Moreover, rPPDK showed better specificity when compared to rGal/GalNAc lectin. In the development of the LFD test, the optimum amount of rPPDK was 0.625 μg per dipstick and the optimum working concentration of colloidal gold conjugated anti-human IgG4 was optical density (OD) 5 (1.7 μg of anti-human IgG4). Evaluation of rPPDK-LFD using ALA patients and controls serum samples showed 87% diagnostic sensitivity and 100% specificity.
CONCLUSION: The developed rPPDK-LFD showed good potential for rapid diagnosis of ALA, and merit further multicentre validation using larger number of serum samples.

Matched MeSH terms: Entamoebiasis/diagnosis*
Application of real-time polymerase chain reaction in detection of Entamoeba histolytica in pus aspirates of liver abscess patients

Othman N, Mohamed Z, Verweij JJ, Huat LB, Olivos-García A, Yeng C, et al.

Foodborne Pathog Dis, 2010 Jun;7(6):637-41.
PMID: 20132028 DOI: 10.1089/fpd.2009.0427

Entamoeba histolytica is the second major cause of liver abscess disease in humans, particularly in developing countries. Recently, DNA molecular-based methods have been employed to enhance the detection of E. histolytica in either pus or stool specimens. In this study, the results of real-time polymerase chain reaction (PCR) to detect E. histolytica DNA in pus from liver abscess cases were compared with those of indirect hemagglutination assay on the corresponding serum samples. Bacterial cultures were also performed on the pus samples for the diagnosis of pyogenic liver abscess. The real-time PCR detected E. histolytica DNA in 23 of 30 (76.7%) pus samples, when compared with 14 of 30 (46.7%) serum samples in which anti-Entamoeba antibodies were detected by indirect hemagglutination assay and 4 of 30 (13.3%) pus samples that showed bacterial infection by culture. The use of real-time PCR is a promising detection method for diagnosis and epidemiology assessment of amoebic liver abscess.

Matched MeSH terms: Entamoebiasis/diagnosis

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